Triple valve.



J. R. SNYDER.

TRIPLE VALVE.

APPLICATION FILED JUNE 10. 1914.

1,231,214o PatentedJune 26, 1917.

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1. R. SNYDER.

TRIPLE .VALVE- APPLICATION FILED JUNE 10, 19M. 1,28L1 Patented June 26, 191?. 2 SHEETS-SHEET 2.

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JACOB BUSH SNYDER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO PERCY E. DONNER, OF PITTSBURGH, PENNSYLVANIA.

TRIPLE VALVE.

Specification of Letters Patent. Patented June 26, I917.

Application filed. June 10, 1914. Serial No. 844,276.

To all whom it may concern Be it known that I, JACOB RUSH SNYDER, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Triple Valves, of which the following is a speci fication.

This invention relates to triple and control valves for air brake systems.

One object of the present invention is to provide means in conjunction with triple and control valves whereby upon service reductions in train pipe pressure the valve is prevented from accidentally going to quick action or emergency position.

IVith present forms of quick action triple and control valves it frequently happens that the main piston fails to move to service application position upon initial service reductions of train pipe pressure. This is due to a variety of causes, such as insuflicient or imperfect lubrication, improperly fitted packing rings, binding of packing rings and pistons, dirt in the valve, and numerous other causes. As a result of the failure of the triple valve to move upon initial re duction of train pipe pressure, substantially the full auxiliary reservior pressure is retained on the auxiliary side of the main piston. Consequently, when the valve does move under a subsequent reduction of train pipe pressure, this excess pressure on the auxiliary reservoir side moves the piston so violently that the standard graduating sprin does not stop the valve in service position, and hence, an undesired quick action or emergency application is brought about. This invariably means the pulling out of draw bars, or some other serious injury to the train.

One of the objects of the present invention is to provide a triple or control. valve particularly adapted for passenger service with means whereby undesired quick action on service reductions of train pipe pressure cannot occur, no matter how much the triple valve piston may stick.

A further object of the invention is to provide a triple or control valve with means for securing an emergency application of the brakes whereby the high pressure of the emergency application is not admitted to the auxiliary reservoir side of the main piston, and each emergency application is not dependent upon the position which the main piston takes, but will be brought about upon sudden reduction of train pipe pressure, even though the main piston of that particular valve should be stuck tightly.

For the attainment of the foregoing objects, the invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the accompanying drawings Figure 1 is a longitudinal section through a valve embodying the invention, the section being taken on'the line l1, Fig. 2, and showing the valve mechanism in normal release or running position; Fig. 2 is a horizontal section with the main piston and valve omitted and showing the main valve seat in plan view; Fig. 3 is a longitudinal section similar to Fig. 1 showing a portion of the valve on the line 33, Fig. 2; Fig. f is a transverse section on the line l-d, Fig. 2; Figs. 5 and 6 are diagrammatic views showing the valve seat in plan and the valve in horizontal section and showing the valve in release and emergency positions respectively; and Fig. 7 is a diagrammatic view of the electrical circuit.

The valve comprises a casing 1 provided at one end (which will be called its inner end) with a flat face 2 for connection to the auxiliary reservoir and brake cylinder, if desired, and is closed at its opposite end by the head or cap 3. In the casing is the chamber lin which works the main piston 5 which is provided with a stem 6 extending into the chamber or bore 7 and serving to actuate the slide valves. The train pipe connection is through a passage 10 extending longitudinally through the bottom portion of the casing 1 and communicating with the main piston chamber a and achamber 11 in the head or cap 3. In the bushing of piston chamber f is the usual charging groove lat which is open when the valve is in normal release and restricted recharging positions, and through which the auxiliary reservoir is charged in the usual way.

In the bore of the valve is a suitable bushing 15 whose lowermost portion forms a valve seat 16 which is provided with the ports and passages shown in Fig. 2, towit, a port 17 which is connected by passage 18 with the train pipe passage 10; a port 19 which is connected by means of a circumferential passage 20 with a longitudinal passage 21 extending to the end face 2 connected to a supplementary reservoir; a large car line with each other and connected by a passage 26 to a chamber 27 (Fig. 1) 011 the outer face of a supplementary piston 28; a port 29 transversely in line with ports 21 and and which is connected by passage 30 with the application chamber; a port 33 which connects through passage 34 with the atmosphere or to a suitable exhaust control valve, said port 33 being the exhaust port for the application chamber and for venting the auxiliary reservoir at time of overreduction of train pipe; a small port 35 con nected to passage 36 for venting the train pipe pressure to the atmosphere at the time of service application; a large port 37 and a small port 38 connected by the passage 39 in the outer face of bushing 15 with a passage 10leading to a chamber 11 on the outer face of a piston 42 which controls a connection between the supplementary reservoir and emergency brake cylinder as will hereinafter more fully appear.

On one side of the main casing 1 is a pro jection 4 1 in which is a chamber 45 for the supplementary piston 28 hereinbefore referred to, and which piston is provided with a stem 46 carrying a pin 4C7 for actuating a supplementary slide valve 18, said slide valve being provided with a cavity 4:9 and moving on a seat 50 in a chamber 51 which is connected. through port 52 with the supplementary reservoir passage 21. The seat 50 is provided with a port 53 leading to the exhaust port 5 1, and with a large port 55 forming (when the valve 18 is in proper position) a. communication between the supplementary reservoir chamber 51 and cham ber 15 which has a connection through the passage 57 with a longitudinal passage 58 in the main casing from which a connection is made to the service brake cylinder.

The casing 1 is also provided with a projection (30 (shown as diametrically opposite the projection 11) and in which is the chamber 41 heretofore referred to. The lower end 01 this chamber is provided with a seat 61 for the emergency brake cylinder control valve 62 which is carried by the piston 1-2, and which valve is normally held to its seat by the spring 63 interposed between the piston 4-2 and the cap (it which closes the outer end of chamber 11. The seat 61 surrounds a port ()5 which communicates through a longitudinal passage 66 in the casing l with the emergency brake cylinder. The annular space 68 surrounding the seat 61 and below the piston 12 communicates through passage 69 with the supplementary reservoir passage 21, so that. supplementary reservoir pressure normally fills said annular space (38 as well as the chamber 51 above supplementary slide valve 18.

In the cap or head 3 is a bushing 72 in which works a piston 73 whose inner face is subject to train pipe pressure in the chamber 11 and whose outer face is subject to an equal pressure in the chamber 71 to which it has gained entrance through the equalizing port 75 in the piston. A quick equalizing groove 76 for chamber 7st is formed in the wall of the bushing 72. The piston 73 is providedwith a hollow stem '77 which actuates a slide valve 78 working on a seat 79 and provided with a cavity 80 and controlling three ports, to-wit, a large exhaust port 81 leading 'to the atmosphere, a smaller exhaust port 82 also leading to the atmosphere, and a port 83 which is connected by means of the passage 84 with the passage 39 leading to the emergency brake cylinder control valve chamber 41/ The stem 77 of the piston 73 is hollow and moves slidably over a sleeve 86 in which is the graduating spring 87 bearing against the outer end or the graduating stem 88 which projects into the main piston chamber 4 as usual. A spring 89 surrounds the sleeve 86Vand assists train pipe pressure in chamber 11 in holding piston 73 in its outermost position, shown in Fig. l.

The movement of piston 73 inwardly under emergency reductions of train pipe pressure is made to close an electric circuit to electrically operate vent valves. This may be accomplished in various ways, but, as shown, the piston is provided with an insulating sleeve 90 whichnormallyseparates the spring contacts 92, and with a metallic circuit closer 91, which when piston 73 moves inwardly under emergency reductions of train pipe pressure, closes the circuit between contacts 92. These contacts extend inwardly through the head 93' and one of these is connected to one side 94 of an electric cir cuit and the other is connected to the opposite side 95 of the electric circuit, in which said circuit there is a suitable source of current 90, and a seriesof magnets 97 for actuating vent valves 98 in the train pipe 99. The several circuit closers 92 are in parallel, as shown in Fig. 7, so that upon the closing of any one thereof the entire series of vent valve magnets 97 are actuated, in order to secure a simultaneous local venting of the train pipe upon each car in case a supplementary piston 73 on any car goes to emergency position. 7

The main piston 5 actuates a pair of slide valves, to wit, a large slide valve 107 which moves upon the seat 16, anda graduating slide valve 108 which moves on the upper face of valve 107. The graduating valve is held between collars 109 on the stem and fits the space between said collars so that it moves at all times with the main piston, whereas the main slide valve 107 does not quite fit the space between collars 111, so that the'piston 5 has a limited amount of movement Without moving the main slide valve. hen the main piston 5 is driven fully inwardly (beyond the position shown in Fig. 1) it contacts with the head 114 of a plunger 115 which is slidable in a yoke 116 and whose inward movement is resisted by spring 117 so that upon said full inward movement of the main piston the spring 117 is put under compression and serves to move the main piston back to the position shown in Fig. 1 upon substantial equalization of pressures on the opposite faces of the main piston. The head 114 is provided with a linger 118 which bears against the end of the main slide valve 107 and moves this valve back with the main piston from the extreme inward position, to-wit, restricted recharging position, to the normal or release posi tion.

The graduating valve 108 is provided in its lower face with a longitudinally arranged cavity 120 having a pair of lateral extensions 121 and 122 respectively.

The main slide valve 107 is cut away at one corner, as at 123, and near its opposite end is provided on one edge with a recess 124, and on its opposite side with a recess 125. Said valve is also provided with several openings therethrough, to-wit, the in clined circular opening 126, an oblong opening 127, another inclined circularopening 128, a similar but larger opening 129, a circular opening 130, and another oblong opening 131, which extends transversely of the valve and is wider on the lower face than on the upper face, and connects through a cored passage 132 with a port 133 in the lower face of said valve. Said valve is also provided on its under face with an L-shaped cavity 134 near one end, a small transverse cavity 135, and a large longitudinal cavity 136 which connects by the cored-out passage 137 with an opening 138.

The main slide valve has seven positions, to-wit, restricted recharging position, which occurs upon sudden increase in train pipe pressure, driving the main piston and valves entirely inwardly or toward the left viewing Fig. 1; full release position shown in Fig. 1; service position, which occurs upon service reductions of train pipe pressure and in which the main piston moves outwardly until it contacts with graduating stem 88; service lap position, in which the main piston and graduating valve move slightly inwardly again, but without moving the main slide valve; overreduction position which occurs when the train pipe pressure has been reduced until the auxiliary reservoir equalizes with the service brake cylinder, and in which the main piston has moved outwardly until the graduating spring 37 is somewhat compressed; over-reduction lap position, in which the main piston and graduating valve are lapped back by the expansion of the graduating spring; and emergency position, which occurs upon sudden reductions of train pipe pressure and in which the main piston moves fully to the right, fully conipressing the graduating spring 87. These positions functionally correspond substantially to the corresponding positions described in my application Serial No. 818,571, filed Feb. 13, 1914. In the present invention no new or different functional elfects are produced in any of the seve 'al positions, except in full release and emergency positions, and consequently only the last two named positions are diagraunnatically illustrated.

In full release position (shown in Fig. :3) the cavity 136 of the main slide valve con nects ports 25 and 29 with exhaust port 323, and consequently the application chamber and also the chamber '27 on the outer face of supplementary piston 28 are vented to v the atmosphere, permitting brake cylinder pressure in chamber 45 to move the supplementary piston 28 and supplementary valve 48 to the position shown in Fig. 4, which exhausts the service brake cylinder to the atmosphere port 54. Supplementary reservoir port 19 registers with port 129 in the main slide valve, and train pipe port 17 registers with port 127 in the main slide valve, and these two ports are connected by the cavity 120 of the graduating valve, thereby charging the supplementary reservoir from the train pipe. Notch 124 in the main valve uncovers port 37 thereby permitting auxiliary reservoir pressure to flow through pa sages 39 and 40 to the chamber 41 on the outer face of the emergency brake cylinder valve piston 42, seating the valve 62 and preventing supplementary reservoir pressure from flowing to the emergency brake cyl inder.

In emergency position, (shown in Fig. (i), the application chamber port 29 is partly uncovered by the main slide valve, per1uit ting the application chamber to be charged from the auxiliary reservoir. Cavity 134 in the main slide valve also connects supplementary reservoir port 19 with ports 24 and 25, thereby permitting supplementary reservoir pressure to flow through passage 26 to the chamber 27 on the outer face of supplementary piston 28, moving the same iuwardly and causing the supplementary valve 48 to connect supplementary reservoir cha1nber 51 to the service brake cylinder. The sudden reduction of train pipe pressure prevents the pressure in chamber 74 equalizing through port 7 5, and consequently the piston 73 moves inwardly, carrying with it the valve 78. This connects train pipe chamber 11 with exhaust port 81, thereby locally venting the train pipe at the car and securing the quick serial action of the brake throughout the train. The cavity of slide gis valve 78 also connects port 83 with exhaust port 82, and as port 83 is connected through passages 84, 39 and &O with the chamber ti on the outer face of the emergency brake cylinder valve piston 42, said chamber 41 is exhausted, so that supplementary reservoir pressure in the annular space 68 underneath piston 42 lifts the latter against the force of spring 63 and with it the valve (32, thereby permitting supplementary reservoir pressure to flow directly to the emergency brake cylinder.

It will be observed that the supplementary reservoir pressure does not enter the chainber 7 on the auxiliary reservoir side of the main piston, and therefore does not build up the pressure on that side of the main piston and prevent the same from being moved back to restricted recharging position upon increase of train pipe pressure. The flow of air from the supplementary reservoir to the brake cylinders is through passages entirely outside of the main valve chamber.

It will be further observed that the graduating stem 88 is so mounted that it's movement does not afi'ect the quick action valve, so that the mere movement of the main piston to emergency position does not bring about the quick action of the brakes. Consequently, the main piston may move to emergency position, as it is likely to do after successive service reductions of train pipe pressure due to sticking of the main piston and valve, without bringing about an uncle sired quick action. The quic action feature is controlled purely and solely by'the supplementary piston 73. Upon all service reductions of train pipe pressure the pressures on the opposite faces of said piston 73 will equalize through the port 75, but this port is not sufliciently large to permit of equalization upon such sudden reductions of train pipe pressure as are made in emergency applications or due to a burst hose. Consequently, in that case the piston 73 moves inwardly, carrying with it the slide valve 78 and opening the exhaust port 81 to the atmosphere to vent the train pipe locally, and its cavity also connecting the port 82 and 83, thereby also venting the chamber -1 above the emergency brake cylinder control valve 62. This gives the necessary local venting of the train pipe to secure quick action throughout the train, and also secures the application of the brakes entirely irrespective of the position of the main piston. Consequently, undesired quick action is absolutely prevented and at the same time quick action and emergency application are insured entirely irrespective of the o'perativeness of the main valve.

hen this supplen'ientary piston 73 moves inwardly, it uncovers groove 76 which is sufliciently large to provide for a quick equallzatlon of pressures on the opposite on any of the other cars of the train have failed to Work, or 1n case the valve on one car moves to emergency position more quickly than that on the others (due for 111- stance to its closer proximity to a burst hose), the electrically actuated vent valves b are energized to secure practically a simultaneous action of the brakes on all cars of the train.

hat I claim is 1. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and effecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a train pipe vent valve arranged to vent the trainpipe, a supplementary valve for controllinga communication from a source of pressure to an emergency brake cylinder, a movable abutment for actuating said supplementary valve, and connections from one side of said movable abutment to the vent valve for venting pressure from said movable abutment to the atmosphere.

2. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and effecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a train plpe vent valve arranged to vent the train pipe, a supplementary valve tor controlling a communication from a source 01: pressure to an emergency brake cylinder, a movable abutment for actuating said supplementary valve, connections from one side of said movable abutment to the vent valve for releasing pressure from said movable abutment, and a movable abutment actuated only upon sudden reductions of train pipe pressure and acting independently of the main valve mechanism for actuating said vent valve.

3. In a triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure, and effecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a train pipe vent valve arranged to vent the train pipe, a supplementary valve for controlling a coimnunication from a source of pressure to an emergency brake cylinder, a movable abutment for actuating said supplementary valve, connections from one side of said movable abutment to the vent valve for releasing pressure from said movable abutment, and ports controlled by the main valve mechanism for admitting pressure to said movable abutment to close said supplementary valve.

4;. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and eifecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a supplementary movable abutment open on one side to train pipe pressure and on the opposite side to an equal trapped pressure, equalizing connections between the two faces of said supplementary abutment arranged so that said movable abutment moves only on sudden reductions of train pipe pressure, and means controlled by said supplementary movable abutment and arranged to open communication from an additional source of pressure to an emergency brake cylinder independently of the main valve mechanism. 1

5. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and efiecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a supplementary movable abutment open on oneside to train pipe-pressure and on the opposite side to an equal trapped pressure, equalizing connections between the two faces of said supplementary abutment aranged so that said movable abutment moves only on sudden reductions of train pipe pressure, and means controlled by said supplementary movable abutment and arranged to open communication from an additional source of pressure to an emergency brake cylinder independently of the main valve mechanism and to simultaneously vent the train pipe.

6. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and efiecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, means controlled by the main slide valve to open communication from an additional source of pressure to the service brake cylinder, and means independent of the movement of the main slide valve arranged to open communication from said additional source of pressure to an emergency brake cylinder.

7. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and efl'ecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmos phere, a supplemental abutment acted upon by pressure from an additional source of pressure in emergency position of the main slide valve to open communication from said additional source of pressure to the service brake cylinder, and a supplementary abutment arranged upon sudden reduction of train pipe pressure to open communication from said additional source of pressure to an emergency brake cylinder, independently of the main valve mechanism.

8. In triple, distributing or control valve mechanism, the combination oi the main movable abutment actuated by variations of train pipe pressure and eilecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmos phere, a supplemental abutment actuated in emergency position of the main slide valve to open communication from an additional source of pressure to the service brake cyl inder, and a supplemental abutment open on one side to train pipe pressure and on the opposite side to an equal trapped pressure, equalizing connections between the two faces of said supplementary abutment so arranged that said movable abutment moves only on sudden reductions of train pipe pressure, and means controlled by said supplementary movable abutment and arranged to open communication from said additional source of pressure to an emergency brake cylinder independently of the main valve mechanism.

9. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and eflecting combina tions between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, and a supplemental abutment arranged upon sudden reductions of train pipe pressure to open communication from an additional source of pressure to an emergency brake cylinder and simultaneously close a circuit serving to actuate train pipe vent valves.

10. In triple, distributing or control valve mechanism, the combination of the main movable abutment actuated by variations of train pipe pressure and effecting combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmos phere, and a supplemental abutment acting independently of the main valve mechanism and arranged upon sudden reductions of train pipe pressure to open communication from an additional source oi? pressure to an emergency brake cylinder and simultaneously close a circuit serving to actuate train pipe ventvalves.

11. An air brake valve mechanism having a main movable abutment arranged to be actuated by variations in train pipe pressure to efi'ect combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a supplementary abutment normally subject to pressure from an additional source whereby the abutment maintains closed an opening from the additional source to an emergency brake cylinder, and means independent of the main abutment for venting the pressure on the supplementary abutment to the atmosphere upon emergency applications to allow said. abutment to open a passage from the additional supply of pressure to the emergency brake cylinder.

12. An air brake *alve mechanism having a main movable abutment arranged to be actuated by variations in train pipe pres sure to effect combinations between the train pipe and auxiliary reservoir and the brake cylinder and atmosphere, a supplementary abutment normally subject to pressure from an additional source whereby the abutment maintains closed an opening from the additional. source to the emergency brake cylinder, graduating means cooperating with the main abutment, and a second supplementary abutment arranged to cooperate with the graduating means to retard sudden movements of the main abutment under service applications and serving under emergency applications to actuate a valve for exhausting the train pipe pressure and the pressure on the first supplementary abutment to atmosphere to allow the first supplementary abutment to move to admit pressure from the additional source to the emergency brake cylinder.

13. A triple valve having a main movable abutment arranged to be actuated by variations in train pipe pressure to efli'ect combinations between the train pipe, auxiliary reservoir and the brake cylinder and atmosphere, means for normally maintaining closed a communication from an additional source of pressure to an emergency brake cylinder, a supplemental valve mechanism, a supplemental movable abutment arranged, when the main abutment is in emergency position, to be actuated to move the supplemental valve mechanism to open communication between the additional source of pressure and the service brake cylinder and also to admit pressure to the means controlling the communication to the emergency brake cylinder, and mechanism arranged to prevent the operation of the means controlling the passage to the emergency brake cylinder irrespective of the action of the main movable abutment except under emergency reductions in train pipe pressure.

14. A triple valve having a main movable abutment arranged to be actuated by variations in train pipe pressure to effect combinations between the train pipe, auxiliary reservoirand the brake cylinder and atmosphere, means for normally maintaining closed a communication from an additional source of pressure to an emergency brake cylinder, a supplemental valve mechanism, a supplemental movable abutment arranged, when the main abutment is in emergency position, to be actuated to move the supplemental valve mechanism to open communication between the additional source of pressure and the service brake cylinder and also to admit pressure to the means controlling thecommunication to the emergency brake cylinder, and means normally preventing operation of the means controlling the passage to the emergency brake cylinder irrespective of the action of the main movable abutment but arranged to be operated by emergency reductions in train pipe pressure 15. A triple valve having a main movable abutment arranged to be actuated by variations in train pipe pressure to effect combinations between the train pipe, auxiliary reservoir and the brake cylinder and atmosphere, means for normally maintaining closed a communication from an additional source of pressure to an emergency brake cylinder, a supplemental valve mechanism, a supplemental movable abutment arranged, when the main abutment is in emergency position, to be actuated to move the supple mental valve mechanism to open communication between the additional source of pressure and the service brake cylinder and also to admit pressure to the means controlling the communication to the emergency brake cylinder, and means normally preventing operation of the means controlling the passage to the emergency brake cylinder irrespective of the action of the main movable abutment but arranged to be operated by emergency reductions in train pipe pressure, said means also being arranged when actuated to vent the train pipe. 7

16. A triple valve having a main movable abutment arranged to be actuated by variations in train pipe pressure to eflect combinations between the train pipe, auxiliary reservoir and the brake cylinder and atmosphere, means for normally maintaining closed a communication from an additional source of pressure to an emergency brake cylinder, a supplemental valve mechanism, a supplemental movable abutment arranged, when the main abutment is in emergency position, to be actuated to move the supplemental valve mechanism to open communication between the additional source of pressure and the service brake cylinder and also to admit pressure to the means controlling the communication to the emergency brake cylinder, and means normally preventing operation of the means controlling the passage to the-emergency brake cylinder irrespective of the action of the 'main movable,

abutment but arranged to be operated by emergency reductions in train pipe pressure, said means also being arranged when actuated to vent the train pipe and close a circuit serving to actuate train pipe vent valves.

17. A triple valve having a main movable abutment arranged to be actuated by variations in train pipe pressure to effect combinations between the train pipe, auxiliary reservoir and the brake cylinder and atmosphere, a second movable abutment arranged to control communication between a supplementary source of pressure and an emergency brake cylinder, a third movable abutment arranged, when the main abutment is in emergency position, to operate a supplementary valve mechanism to admit pressure from the additional source to the service brake cylinder and to the second abutment, and a fourth abutment normally preventing operation of the second abutment irrespective of the action of the main movable abutment, but arranged to be actuatcd by emergency reductions in train pipe pressure to vent pressure from the second abutment to permit the same to move to ad mit pressure from the additional source to the emergency brake cylinder.

five cents 18. A triple valve having a main movable abutment arranged to be actuated by va' riations in train pipe pressure to efiect combinations between the train pipe, auxiliary reservoir and the brake cylinder and at mosphere, a second abutment arranged to control a communication between a supplementary sou ce of pressure and an emergency brake cylinder, a third abutment arranged when the main abutment is in emergency position to actuate a supplementary valve mechanism to admit pressure from the supplementary source to the service brake cylinder and to one side of the second abutment, and means independent of the main movable abutment for controlling the pressure on the opposite side of the second abutment, said means being arranged to operate only upon emergency reductions of train pipe pressure irrespective of the action of the main movable abutment under other reductions in train pipe pressure.

In testimony whereof, I have hereunto set my hand.

JACOB RUSH SNYDER. Witnesses:

ELBERT L. HYDE, GLENN H. Lnnnsonn.

each, by addressing the Commissioner of Patents,

Washington, D. C. 

